Impact resistant high air retention bladders

Abstract

The invention relates to methods of manufacturing bladders for footballs comprising (a) applying a thin layer of coating solution to a polyurethane film, said solution consisting of polyvinylidene, ethylene vinyl alcohol, polyamide polymers or vinylidene chloride copolymers, and organic solvents; (b) evaporating said solvents; (c) optionally repeating steps (a) and (b); (d) forming said coated film into a bladder. Said invention also relates to products of said methods.

I claim: 
     
       1. The method of manufacturing bladders for footballs or the like, comprising: (a) applying a thin layer of a coating solution to one side of a polyurethane film capable of being formed into inflatible bladders, said film having a thickness of from 3 to 12 mils, said solution consisting essentially of a selected coating resin dissolved in an organic carrier solvent which does not dissolve or react with the polyurethane film, said coating resin being selected from the class consisting of polyvinylidene polymers and copolymers of vinylidene chloride with other vinyl monomers, ethylene vinyl alcohol polymers, and polyamide polymers, said coating solution also containing from 3 to 18% by weight of an organic attack solvent miscible with said carrier solvent and which is capable of dissolving the polyurethane of said filing, said resin being present in a coating concentration;   (b) rapidly evaporating the solvent from said applied coating solution;   (c) optionally repeating said applying and evaporating steps, if required, the resulting dried coating comprising a resin layer fused with said polyurethane film and having a thickness of from 0.3 to 1.2 mils; and   (d) forming said coated film ito inflatible bladders with said coated layers on the outside thereof, whereby high air retention polyurethane bladders are provided which resist impact delamination.   
     
     
       2. The bladders manufactured by the method of claim 1. 
     
     
       3. The method of claim 1 in which said resin is a copolymer of vinylidene chloride and vinyl chloride, said carrier solvent being a ketone solvent and said attack solvent being selected from the class consisting of tetrahydrofuran, dimethyl foramide, and dimethyl sulfoxide. 
     
     
       4. The method of claim 1 in which said attack solvent is present in an amount of from 5 to 15% by weight of said coating solution. 
     
     
       5. The method of claim 1 in which said coating resin is an ethylene vinyl alcohol polymer, said carrier solvent is an alcohol solvent, and said attack solvent is selected from the class consisting of tetrahydrofuran, dimethyl foramide, and dimethyl sulfoxide. 
     
     
       6. The method of claim 1 in which said coating resin is a polyamide resin, said carrier solvent is a mixture of pyrrolidine and a ketone solvent, and said attack solvent is selected from the class consisting of tetrahydrofuran, dimethyl foramide, and dimethyl sulfoxide. 
     
     
       7. The method of manufacturing bladders for footballs or the like, comprising: (a) applying a thin layer of a coating solution to one side of a polyurethane film capable of being formed into inflatible bladders, said film having a thickness of from 3 to 12 mils, said solution consisting essentially of a coating resin comprising a copolymer of vinylidine chloride and vinyl chloride dissolved in an organic carrier solvent which does not dissolve or react with the polyurethane film, said coating solution also containing from 5 to 15% by weight of an organic attack solvent miscible with said carrier solvent and which is capable of dissolving the polyurethane of said film, said resin being present in a coating concentration;   (b) rapidly evaporating the solvent from said applied coating solution;   (c) optionally repeating said applying and evaporating steps, if required, the resulting dried coating comprising a resin layer effectively fused with said polyurethane film and having a thickness of from 0.3 to 1.2 mils; and   (d) forming said coated film into inflatible bladders with said coated layers on the outside thereof, whereby high air retention polyurethane bladders are provided which resist impact delamination.   
     
     
       8. The bladders manufactured by the method of claim 7. 
     
     
       9. The method of claim 7 in which said film has a thickness of from 3 to 8 mils and said dried coating has a thickness of from 0.3 to 0.8 mils. 
     
     
       10. The bladders manufactured by the method of claim 9.